The invention relates to production of circuits in which items such as glue deposits, solder deposits, and electronic components are deposited on a substrate such as a printed circuit board.
Heretofore, there have been many developments in the field of screen printing, component dispensing, and component placement to achieve excellent tolerances and efficiencies in circuit production machines. Yield is maintained by manual adjustment of machine parameters according to visual inspections and inspection machine circuit quality outputs. There is considerable room for error in this approach, and accordingly yields are often not as high as desired.
The invention is therefore directed towards providing a circuit production method having improved yields.
Another object is to achieve the above with little modification of existing production equipment.
According to the invention, there is provided a method of producing a circuit in which a production machine deposits an item onto a substrate and a measurement machine inspects the quality, characterised in that the method comprises the further steps of:
a closed loop controller capturing measurement data from said measurement machine;
the closed loop controller using said measurement data to generate a control signal for the production machine; and
the production machine using said control signal for improved process control.
In one embodiment, the closed loop controller uses configuration rules associated with the production machine to generate the control signal.
In one embodiment, the closed loop controller also uses production data indicating which parts of the production machine were involved in depositing items, to generate the control signal.
In one embodiment, the closed loop controller uses an identifier of a substrate to generate the control signal.
In one embodiment, the production data is static, in which the production machine part which deposits each item does not change during a production run.
In another embodiment, the production machine is a component placement machine and said placement machine does not use a different nozzle to make a subsequent placement after a component has been mis-picked.
In one embodiment, the dosed loop controller dynamically receives feed-forward production data from the production machine in real time.
In one embodiment, the production data associates parts of the production machine with deposited items.
In a further embodiment, the production machine is a component placement machine and said production data associates parts at machine, beam, turret, head, nozzle, and feeder levels with deposited components.
In one embodiment, the closed loop controller dynamically generates an output to convey the measurement data to a process engineer.
In one embodiment, said output comprises accuracy charts graphically illustrating accuracy of a deposited item.
In one embodiment, the closed loop controller starts feeding back the control data after generating said output and receiving an instruction from a process engineer.
In one embodiment, both the production machine and the measurement machine automatically detect a substrate identifier, and the measurement machine incorporates said identifier in the measurement data, for correlating the production data with the measurement data.
In one embodiment, the substrate identifier is a bar code and the production machine and the measurement machine read said bar code.
In one embodiment, the closed loop controller comprises a measurement server and a closed loop client, the measurement server captures data from the measurement machine, and the closed loop client generates the control signal and feeds it back to the production machine.
In one embodiment, there is one measurement server associated with each measurement machine.
In another embodiment, there is one closed loop client associated with each production machine.
In one embodiment, the measurement server uses said measurement data and said production data to generate correlated data, and feeds the correlated data to the closed loop client.
In one embodiment, the closed loop client uses the correlated data to generate the control signal according to configuration rules associated with the associated production machine.
In one embodiment, the closed loop client generates the process engineer output according to correlated data received from the measurement server.
In one embodiment, the measurement server comprises a data processing server, the closed loop client comprises a data processing client, and the client and the server communicate with each other using the client/server architecture.
In one embodiment, the configuration rules define conditions to trigger transmission of a control signal.
In one embodiment, a condition is that an offset outside a tolerance occurs greater than a pre-set number of times.
In one embodiment, a condition is that an offset outside a high threshold occurs once.
In one embodiment, the closed loop controller includes a production machine shut-down instruction in the control signal when an alarm condition is met.
According to another aspect, the invention provides a closed loop controller comprising:
means for automatically capturing measurement data from a measurement machine for inspecting a circuit having deposited items; and
means for using said measurement data to generate a control signal for a production machine, and for feeding said control signal back to the production machine.
In one embodiment, the closed loop controller comprises:
a measurement server comprising means for capturing said measurement data and for correlating the measurement data with production data indicating which parts of the production machine were involved in depositing items, and for feeding back correlated data, and
a closed loop client comprising means for receiving the fed back correlated data and for using said correlated data to generate the control signal according to configuration rules.
In one embodiment, the closed loop controller comprises means for generating a process engineer output incorporating said measurement data.
In one embodiment, the closed loop client comprises means for generating said output using the correlated data.
In one embodiment, the closed loop client comprises means for initiating feedback of a control signal upon receipt of a user instruction.
In one embodiment, the closed loop controller comprises means for dynamically receiving feed-forward production data from the production machine.
In one embodiment, the measurement server comprises a data processing server, the closed loop client comprises a data processing client, and the client and the server comprise means for communicating with each other using the client/server architecture.
In one embodiment, the measurement server has a class structure with a method for production data acquisition, and a method for measurement data acquisition.
In one embodiment, the measurement server has a method for raising a defect alarm event.
In one embodiment, the closed loop client has a class structure with a method for each of production data acquisition, correlated data acquisition, and transmission of a control signal.
In one embodiment, the closed loop client has a method for production machine shut down.